The invention relates to a device for automatically adjusting the height of the deflection fitting of a safety belt in vehicles, in particular motor vehicles having a vertical guide rail attached to the vehicle body and an anchoring element which guidingly carries the deflection fitting in a vertically displaceable manner in the guide rail, and wherein the adjusting mechanism is displaceable for holding the anchoring element in a set vertical position and wherein a locking device is effective in the case of extreme vehicle deceleration for locking the anchoring element at the guide rail. The locking element can be displaced transversely to the vertical displacement direction of the anchoring element, and is coupled to the anchoring element and has a row of locking teeth capable of being pushed into a corresponding row of holes in the guide rail by means of a downward movement relative thereto of the anchoring element.
Devices of this kind, by means of which the deflection fitting of the safety belt can be adjusted in height via the adjusting mechanism as a function of the position of a vehicle seat, serve to adjust the upper anchoring point of the safety belt automatically to the particular size of the user of the seat. In this context, the deflection fitting is held in a particular set vertical position by the adjusting mechanism, which can be designed using a Bowden cable or a push-pull element connected to the seat, but is not fixed in this position. In order to prevent an undesirable displacement, or loading of the deflection fitting on the adjusting mechanism, which cannot take such loading during the event of sharp braking, or of vehicle collision, the locking device locks the deflection fitting directly to the guide rail and thus to the vehicle body.
In German Offenlegungsschrift 2,655,015, the anchoring element and the locking element are arranged in a large volume recess on a slide which slides in the guide rail. Extending at approximately 45.degree. to its displacement direction, the anchoring element has a wedge surface against which the locking element rests by an identical wedge surface under the action of a lifting spring attached to the locking element and supported on that side of the guide rail which carries a row of locking holes. The adjusting mechanism engages the slide in the displacement direction of the latter. As soon as a force, which exceeds the tensile force exerted on the belt by the user of the belt during normal driving, is exerted on the belt, the force exerted on the wedge surface of the locking element by the anchoring element connected to the deflection fitting via the wedge surface of the anchoring becomes greater than a spring force of a lifting spring. The lifting spring is compressed and the locking element is displaced towards the row of holes in the guide rail until the row of locking teeth engages the row of holes. The anchoring element is thus directly fixed via the locking element to the guide rail and thus to the car body and all the tensile forces exerted on the belt are directed into the car body via the deflection fitting. Alteration of the vertical position of the deflection fitting is not possible, nor is loading of the adjusting mechanism.
However, a precondition for the satisfactory functioning of this known device is that the adjusting mechanism should resist the downward movement of the slide at the moment when downwardly directed tensile forces are exerted on the deflection fitting and thus on the anchoring element and this resistance must be greater than the spring force of the lifting spring. If this is not the case, the slide is displaced downwards by the anchoring element via the locking element and a transverse movement of the locking element against the force of the lifting spring does not occur. Although such matching of the locking mechanism and the lifting spring can be achieved, the reliability of the device in the long term cannot be guaranteed. Moreover, the functioning of the device depends on the secure locking of the seat to the floor of the vehicle. If this is not guaranteed, the slide is displaced with the seat and the locking device cannot become operative. It is then not possible to prevent the deflection fitting from slipping, with the disadvantage consequences for the user of the belt.
An object on which the invention is based is to provide a device of the type above-mentioned wherein the locking mechanism functions reliably long term and uninfluenced by faults elsewhere in the belt system, such as, for example, on an unlocked vehicle seat, and thus offers the user of the belt effective protection from injury at all times.
According to the invention, an object thereof is achieved by automatically adjusting the height of the deflection fitting of a safety belt having a vertical guide rail attached to the vehicle body and an anchoring element which guidingly carries the deflection fitting in a vertically displaceable manner in the guide rail, and wherein the adjusting mechanism is displaceable for holding the anchoring element in a set vertical position and wherein a locking device is effective in the case of extreme vehicle deceleration for locking the anchoring element at the guide rail. The locking element can be displaced transversely to the vertical displacement direction of the anchoring element, and is coupled to the anchoring element and has a row of locking teeth capable of being pushed into a corresponding row of holes in the guide rail by means of a downward movement relative thereto of the anchoring element. The adjusting mechanism acts directly on the anchoring element by having a deceleration sensor interact with the locking element in such a way that when a predetermined vehicle deceleration value is exceeded it blocks a downward movement of the locking element at least temporarily.
The sensor, which detects sharp braking or a collision of the vehicle, prevents the downward movement of the locking element, caused by increased belt loading, independently of the adjusting mechanism. With the locking element blocked from downward movement, the locking element is displaced sidewards by the continuing downward movement of the anchoring element caused by belt loading, so that a row of locking teeth enters a row of holes in the guide rail very rapidly and reliably. The entry of the row of locking teeth is thereby positively controlled. Sensors for detecting deceleration have long been used in vehicles for various protection devices and operate very reliably. The locking device functions even when the seat is loose, so that in this case, in the event of a possible crash, the seat and the passenger are restrained by the safety belt.
An advantageous embodiment of the invention is to prevent a part of the locking force being directed into the sensor and there causing function-impairing damage. By having the deceleration sensor act on the locking element so that as the row of locking teeth on the locking element begins to engage the row of holes in the guide rail, the connection between sensor and locking element is cancelled and thus this prevents a part of the locking force being directed into the sensors, and thus causing a function impairing damage.
A further advantage is obtained by the deceleration sensor being arranged on the guide rail with a ball which shifts when the vehicle deceleration exceeds the predetermined value and including a swivellably mounted swivelling lever with locking nose, and wherein a control member, which carries a toothed strip which projects into the swivelling region of the swivelling lever, interacts with the locking nose of the swivelling lever to limit its down movement.
Another advantageous embodiment of the invention is obtained by having the tooth spacing of the toothed strip and the tooth spacing of the row of locking teeth of equal magnitude and with the swivelling lever arranged such that when the locking teeth and the row of holes are located opposite one another, the locking nose can fall into a gap between the teeth of the toothed strip. This ensures that when the locking element is blocked by the sensor, the teeth of the row of locking teeth are aligned exactly with the holes in the row of holes and can thus enter the latter unhindered by means of transverse displacement of the locking element.
A further advantage is obtained by having the control member rigidly connected to the locking element in such a way that it takes part in the latter's displacement movement transverse to the displacement direction of the anchoring element and in that the swivelling lever and the control element are arranged in such a manner with respect to one another that during a displacement movement of the locking element prior to locking teeth fully engaging the row of holes, the toothed strip is transversely displaced by a distance which releases the locking nose.
Another advantage is obtained by having the anchoring element formed with a base plate, which is laterally guided in a U-shaped guide rail, and a cover plate firmly connected to the base plate while leaving an intermediate space therebetween for a flat locking element to be held in a transversely displaceable manner. Locking teeth are arranged along a lateral edge of the locking element and cooperating holes are arranged in an arm of the U-shaped guide rail. Also, the base plate is bent towards the cover plate in the displacement direction, above and below the locking element in the plane of the locking element, and has a bevel surface which extends at an acute angle to the longitudinal axis of the plate in the downward displacement direction to form a sliding surface. A tension spring mechanism engages on the locking element and on the base plate and against a sliding surface, formed by a second bevel surface on the locking element, to bias the locking element open. The cover plate has at least one nose which projects towards the locking element and protrudes through a locking element opening, which edges limit the displacement movement of the locking element transverse to the displacement direction of the base and cover plate.
Other edges of the opening in the locking element cooperate with noses on the cover plate to carry the locking element with the base and cover plate during vertical movement.
Still another advantage lies in having the deflection fitting secured to a screw bolt on the base plate, which bolt protrudes through a longitudinal slot which extends through a web of the U-shaped guide rail over the displacement range of the base and cover plate.
These and other objects, features, and advantages of the present invention will become more apparent from the following description when taken in connection with the accompanying drawings which show, for the purposes of illustration only, one embodiment in accordance with the present invention, and wherein: